To satisfy demands for wireless data traffic which have been increasing since the commercialization of a 4th-generation (4G) communication system, efforts have been made to develop an advanced 5th-generation (5G) or pre-5G communication system. For this reason, the 5G or pre-5G communication system is called a beyond 4G network communication system or post long-term evolution (LTE) system.
To achieve high data rates, implementation of the 5G communication system in an ultra-high band (mmWave band) (e.g., a frequency band such as a 60-GHz band) is under consideration. Beamforming, massive multi-input multi-output (massive MIMO), full dimensional MIMO (FD-MIMO), array antennas, analog beamforming, large-scale antennas have been discussed for the 5G communication system in order to mitigate the pathloss of waves and increase the propagation distance of waves in the ultra-high frequency band.
In addition, evolved small cell, advanced small cell, cloud radio access network (cloud RAN), ultra-dense network, device-to-device (D2D) communication, coordinated multi-points (CoMP), interference cancellation, etc. have been developed in the 5G communication system, for the purpose of improving a network in the system.
Besides, hybrid frequency shift keying (FSK) and quadrature amplitude modulation (QAM) (hybrid FSK and QAM (FQAM)), and sliding window superposition coding (SWSC), which are advanced coding modulation (ACM) schemes, and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA), which are advanced access techniques, are under development in the 5G communication system.
In view of mobility and portability inherent to portable phones, location-based service (LBS) has been considered to be one of killer applications since the beginning of mobile communication.
Particularly, the drastic growth of smartphones has strengthened the current status of the LBS as a killer application. For example, iPhones and Android phones have defined the LBS as a killer application and have formed the basis of LBS activation by supporting hardware in the global positioning system (GPS) and wireless local area networks (WLANs), and providing various techniques and databases (DBs) for the LBS.
For example, iPhone operating system (iOS)-based smartphones and Android operating system (OS)-based smartphones detect locations based on cellular base stations (BSs), and provide various LBSs based on the detected locations.
As described above, iOS-based smartphones and OS-based smartphones provide a variety of LBSs, and there are various positioning precision requirements for the LBSs.
Table 1 below lists LBSs provided by various organizations and positioning precision requirements to support the LBSs.
TABLE 1Service classificationDescriptionRequirementsSourcePublic safetyIndoorE911 Call~50mFCC ['15,and rescue(horizontal)February]service~30m(vertical)OutdoorMissing10~50mETRI ['06,person/survivorMarch]positioningCommercialIndoorAdvertisement  ~0.5mMETISservicetransmission in2020 ['13,shopping mallApril]OutdoorAmbient75~125mETRI ['06,information (e.g.,March]store) searchNavigation10~50mVehicleCollision  ~0.5mMETIScommun-prevention/2020 ['13,icationautomaticApril]driving
As illustrated in Table 1, high-precision positioning may be needed to satisfy various positioning precision requirements. It may be difficult to perform such high-precision positioning by GPS-based positioning, WiFi-based positioning, and BS-based positioning, which will be described below in detail.
First, although GPS-based positioning may achieve a relatively high precision, for example, below an error of 5 m, at least three satellite signals are required to achieve this high precision. However, since signals from satellites are blocked in an urban region populated with a large number of buildings such as a dense urban environment, and an indoor environment, GPS-based positioning is not viable in the urban region and the indoor environment.
Secondly, a precision error, for example, below 5 m may be achieved in the indoor environment by WiFi-based positioning. However, it is impossible to use WiFi-based positioning for an LBS such as indoor navigation listed in Table 1 with the current precision. Moreover, WiFi-based positioning is not viable in an outdoor environment in which a WiFi access point (AP) is not installed.
Thirdly, BS-based positioning may not be preferred due to its error of tens of meters to a few kilometers.
As such, GPS-based positioning, WiFi-based positioning, and BS-based positioning have limitations in positioning precision and use environment. Accordingly, there is a need for an additional positioning scheme to provide various LBSs.
Further, Table 2 lists various applications which provide LBSs by GPS-based positioning, WiFi-based positioning, and BS-based positioning. The applications as listed in Table 2 below may be used very conveniently for the purpose of detecting the location of a device or the location of its correspondent device.
TABLE 2CategoryApplicationLocationNavigationT-Map, KT olleh Navi, U+Navi, NationaldetectionNavigation Driver Kim, etc.for deviceDrivingReal-time guide of accident/construction sites:itselfexpressway guide, etc.Search for nearby bus stops/gas stations/parking lots: Seoul Bus, Parking Park,Offinet, etc.Notify arrival at destination: Metro Wizard,Smarter Subway, etc.ExerciseMeasure movement path/speed/exerciseassistanceamount: Nike+GPS, bikemate, Run-GPS,Mobitee golf, etc.Public safetyReporter identification/positioning: One-TouchSOS Public Relief Service, etc.TravelRecommend sightseeing places/travel sites/travel course, and navigate: KoreaGuseokguseok, Wishbeen, etc.Location detection forMeWe, Famy, Life360, iSharing, etc.correspondent device
However, the applications as listed in Table 2 require a user's direct activation of a corresponding function, that is, a positioning function.
For example, to receive the LBS, the user activates a GPS function, a WiFi function, and a Bluetooth function, or directly executes a corresponding application so that the application activates the GPS function, the WiFi function, and the Bluetooth function.
Therefore, various applications which provide LBSs by GPS-based positioning, WiFi-based positioning, and BS-based positioning as listed in Table 2 may not be viable in an emergency situation such as a natural disaster like earthquake or tsunami, or a human-caused disaster such as a fire or poor construction, which results in building collapse and burial of persons. This is because a buried person may be placed in a situation in which it is difficult to activate a corresponding function. In addition, even though the corresponding function is activated, infrastructure in the surroundings may be destroyed in such an emergency situation as building collapse, making WiFi-based positioning impossible. Since the buried person is indoors, GPS-based positioning may be impossible.
Meanwhile, the above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.